[APInt] Use isSubsetOf, intersects, and bit counting methods to reduce temporary APInts

This patch uses various APInt methods to reduce temporary APInt creation.

This should be all of the unrelated cleanups that got buried in D32376(creating a KnownBits struct) as well as some pointed out by Simon during the review of that. Plus a few improvements to use counting instead of masking.

I've left out any places where we do something like (KnownZero & KnownOne) != 0 as I plan to add a helper method to KnownBits to ask that question and didn't want to thrash that code an additional time.

Differential Revision: https://reviews.llvm.org/D32495

llvm-svn: 301338

6 files changed, 11 insertions, 13 deletions

diff --git a/llvm/lib/Analysis/InstructionSimplify.cpp b/llvm/lib/Analysis/InstructionSimplify.cpp
index febaf302ef3..5670746284e 100644
--- a/llvm/lib/Analysis/InstructionSimplify.cpp
+++ b/llvm/lib/Analysis/InstructionSimplify.cpp
@@ -1376,8 +1376,7 @@ static Value *SimplifyShift(Instruction::BinaryOps Opcode, Value *Op0,
   // If all valid bits in the shift amount are known zero, the first operand is
   // unchanged.
   unsigned NumValidShiftBits = Log2_32_Ceil(BitWidth);
-  APInt ShiftAmountMask = APInt::getLowBitsSet(BitWidth, NumValidShiftBits);
-  if ((KnownZero & ShiftAmountMask) == ShiftAmountMask)
+  if (KnownZero.countTrailingOnes() >= NumValidShiftBits)
     return Op0;
 
   return nullptr;
@@ -3372,7 +3371,7 @@ static Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
       APInt LHSKnownOne(BitWidth, 0);
       computeKnownBits(LHS, LHSKnownZero, LHSKnownOne, Q.DL, /*Depth=*/0, Q.AC,
                        Q.CxtI, Q.DT);
-      if (((LHSKnownZero & *RHSVal) != 0) || ((LHSKnownOne & ~(*RHSVal)) != 0))
+      if (LHSKnownZero.intersects(*RHSVal) || !LHSKnownOne.isSubsetOf(*RHSVal))
         return Pred == ICmpInst::ICMP_EQ ? ConstantInt::getFalse(ITy)
                                          : ConstantInt::getTrue(ITy);
     }
diff --git a/llvm/lib/Analysis/ValueTracking.cpp b/llvm/lib/Analysis/ValueTracking.cpp
index 02db651a1f9..b39783dbf77 100644
--- a/llvm/lib/Analysis/ValueTracking.cpp
+++ b/llvm/lib/Analysis/ValueTracking.cpp
@@ -1934,12 +1934,12 @@ bool isKnownNonZero(const Value *V, unsigned Depth, const Query &Q) {
       // The sign bit of X is set.  If some other bit is set then X is not equal
       // to INT_MIN.
       computeKnownBits(X, KnownZero, KnownOne, Depth, Q);
-      if ((KnownOne & Mask) != 0)
+      if (KnownOne.intersects(Mask))
         return true;
       // The sign bit of Y is set.  If some other bit is set then Y is not equal
       // to INT_MIN.
       computeKnownBits(Y, KnownZero, KnownOne, Depth, Q);
-      if ((KnownOne & Mask) != 0)
+      if (KnownOne.intersects(Mask))
         return true;
     }
 
@@ -2056,7 +2056,7 @@ bool MaskedValueIsZero(const Value *V, const APInt &Mask, unsigned Depth,
                        const Query &Q) {
   APInt KnownZero(Mask.getBitWidth(), 0), KnownOne(Mask.getBitWidth(), 0);
   computeKnownBits(V, KnownZero, KnownOne, Depth, Q);
-  return (KnownZero & Mask) == Mask;
+  return Mask.isSubsetOf(KnownZero);
 }
 
 /// For vector constants, loop over the elements and find the constant with the
@@ -4289,7 +4289,7 @@ static bool isTruePredicate(CmpInst::Predicate Pred,
         APInt KnownZero(BitWidth, 0), KnownOne(BitWidth, 0);
         computeKnownBits(X, KnownZero, KnownOne, DL, Depth + 1, AC, CxtI, DT);
 
-        if ((KnownZero & *CA) == *CA && (KnownZero & *CB) == *CB)
+        if (CA->isSubsetOf(KnownZero) && CB->isSubsetOf(KnownZero))
           return true;
       }
 
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
index 0ea1c7be422..6890b061e62 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
@@ -1393,7 +1393,7 @@ static Instruction *foldCttzCtlz(IntrinsicInst &II, InstCombiner &IC) {
   // zero, this value is constant.
   // FIXME: This should be in InstSimplify because we're replacing an
   // instruction with a constant.
-  if ((Mask & KnownZero) == Mask) {
+  if (Mask.isSubsetOf(KnownZero)) {
     auto *C = ConstantInt::get(IT, APInt(BitWidth, NumMaskBits));
     return IC.replaceInstUsesWith(II, C);
   }
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp b/llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp
index 5222cd498f3..4dabbda66b9 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp
@@ -453,11 +453,11 @@ Value *InstCombiner::SimplifyDemandedUseBits(Value *V, APInt DemandedMask,
 
       // If we are known to be adding/subtracting zeros to every bit below
       // the highest demanded bit, we just return the other side.
-      if ((DemandedFromOps & RHSKnownZero) == DemandedFromOps)
+      if (DemandedFromOps.isSubsetOf(RHSKnownZero))
         return I->getOperand(0);
       // We can't do this with the LHS for subtraction.
       if (I->getOpcode() == Instruction::Add &&
-          (DemandedFromOps & LHSKnownZero) == DemandedFromOps)
+          DemandedFromOps.isSubsetOf(LHSKnownZero))
         return I->getOperand(1);
     }
 
diff --git a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
index e9152b8e88b..1c2c763cea0 100644
--- a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
+++ b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
@@ -4380,7 +4380,7 @@ static bool EliminateDeadSwitchCases(SwitchInst *SI, AssumptionCache *AC,
   SmallVector<ConstantInt *, 8> DeadCases;
   for (auto &Case : SI->cases()) {
     APInt CaseVal = Case.getCaseValue()->getValue();
-    if ((CaseVal & KnownZero) != 0 || (CaseVal & KnownOne) != KnownOne ||
+    if (KnownZero.intersects(CaseVal) || !KnownOne.isSubsetOf(CaseVal) ||
         (CaseVal.getMinSignedBits() > MaxSignificantBitsInCond)) {
       DeadCases.push_back(Case.getCaseValue());
       DEBUG(dbgs() << "SimplifyCFG: switch case " << CaseVal << " is dead.\n");
diff --git a/llvm/lib/Transforms/Vectorize/LoadStoreVectorizer.cpp b/llvm/lib/Transforms/Vectorize/LoadStoreVectorizer.cpp
index 4409d7a404f..f709d6a516e 100644
--- a/llvm/lib/Transforms/Vectorize/LoadStoreVectorizer.cpp
+++ b/llvm/lib/Transforms/Vectorize/LoadStoreVectorizer.cpp
@@ -331,8 +331,7 @@ bool Vectorizer::isConsecutiveAccess(Value *A, Value *B) {
     APInt KnownZero(BitWidth, 0);
     APInt KnownOne(BitWidth, 0);
     computeKnownBits(OpA, KnownZero, KnownOne, DL, 0, nullptr, OpA, &DT);
-    KnownZero &= ~APInt::getHighBitsSet(BitWidth, 1);
-    if (KnownZero != 0)
+    if (KnownZero.countTrailingZeros() < (BitWidth - 1))
       Safe = true;
   }